Bomb fuse



P 1948- J. B. Ma LEAN ET AL 2,449,170

BOMB FUSE 2 Sheets-Sheet 1 Filed. Nov. 8, 1943 INVENTORS JOHN 8. MACLEAN [lg 54X E. SCHLENKEE A TTORNEX Sept. 14, 1948. J. B. MacL AN ETAL2,449,170

BOMB FUSE 2 Filed Nov. a, 1943 v 2 Sheets-Sheet 2.

65 6 g 4 ea 82 a Flf Z v INVENTORS JOHN 5. WC LEAN ggi AX E.-.$CHLENKEE.

ATTORNEY.

v Figs-4 1s a schematicrdiagramillustrating Patented Sept. 14, 1948 smates "HOIVIB FUSE JohnfiBL' MacLean and Maxi Schlenker, Peru; i

111., assignors .vtoiGeneral' :Time- Instruments e -Corporation;iNewYork, N .--Y., a corporationl of- Delaware "ApplicationNovember 8, 1943,Srial No. 509;394

'4':Clalms. (Gl.102-84)- This invention relates in general i-to" bbmb'fuze's :and "more particularly to v: fuzes' for -aerial dnop bombsarranged to' det'onate -a==predetermined time interval after beingdropped from-a plane; The mainobject-l fthe invention is -to provide amechanical time fuze of :this type which is normally safe and which arms#only a predetermined- I interval 1 after '-"the- "bomb leaves theplane.

According toone feature of the invention, the detonator is carriedby *a-'movaible memberand is :normally held in a safe position but of "thepath of 'movementof the-'ilrinepin; 'The release of the =detonator toarmed position 1 iscontrolled by *the same timing mWem'ent whichcontrols the release-of the fiiing 'pin 'to detonate the bomb.

Another feature of the-invention resides in -the manner in which thedetonator slider is held'in safety position and releasedby'th'e-timirig' movement.'

According to a further feature-ofthe invention, the timing movementreleases the de'tonat'or slider to armed position after a predeterminedfixed interval which is less than theshortes't' interval= to which thefiring -pin release mechanism maybeadjusted In some cases withcertaintypes (if-bombs it is "the -'practice= to i install a fuze on thetai l of the b-ombas well as-0n thenose' of the bombJ This is an addedprecaution to insure-"detonation of the bomb atthe desired tim'e 'sinceif one fuze should fail the --other will detonatethe bomb. 'The'fuzesmaybe similar in all respects exc'ept that the vane for the tail fuzeis-some'wh'at longer;

to "insure =its proper operation by theair stream, and the arrangementof the-ball bearing assembly=is reversed fromthat-"'of-the nose fuze'x*For the purpose'ofillustration,*a'tail fuzeis disclosed and describedherein;

The aforementioned "objects "and" features of the invention andothers'not speciflcally'fpointed out above will become apparent andaclear. understandingof the invention mayibethad from a perusal of theifollo'wing specification. whenread'" in connection with theaccompanyingLdzawing,

comprising-Figs. 1 to 1, inclusive, inwhich:

, Fig.- 1 is a cross-sectional viewsof a complete tail iuze embodying:the present invention Y Fig.t2 isa-cross-sectionetaken alongethe linezflliofFigil;

Fig; 3 :is .a cross-section taken along cthe line 3 .3 0f -Fig. 1;.

'which' normallyllies:within thei groove'ri inner surface 50f bodyi 'lwhen ..-the; -head:is-;inserted' in the body 1 a: pluraii-tyiofescrewstsuchsias fl? aretscrewed 'do-wn 'ln iorde'rwto push:.thezspring v2relationshipr.-and -'operation 0f :therfiri-ng pin releasemechanism;zandz Figi f5 is 25 pBlSpeOtiVe VleWaOf thevheadnendrof:the.:fuze.

Referring; in" detail to the '3 drawingeythecfuze consistsz'essentiallyof ia 'body sectionl 'and- -':a

lieadassemblyr 2 rotatablyr-secured theretofi {Ihe head assembly E2wcomprises a'casing, head-4 i havingca projecting portion: which extends:into the :cavity withinrthe "body 1|. Theihead-is retained within. the:body by; means :of eaizspring '2 wire -:5

wire "5 :part way into accomplementaryzzgnoove:in the cylindricalsurface of headA: This .wsprm'g gether and rat tthe sametime permits theZrhead fto' 'be rotated in ror'der ito :adiust'.the-etimeisetting of:the fuze :as will =be-explained later;

Asaran additional 1 precaution: the ccyl indrical surfaceiofthe :reducedportion of rhead TA is-iprovidedwith-.a-viurtherrgroove :6:and ';thebodyi'l ls hubibeingaslabbed: vonzone side 'so; that: the: vane :canmotturn thereon: The'vanevlil: is j retained against-ta shoulder :onrtheinner ballaraceclfi '-:by

provided withzholes-tr'ig adapted to receive aasuitable :wrench: sothat" the nut-imay be tightened on thefi'hub tosecurely 1clampgthervan'eontoithe inner: :bail .race.

Q'Ihe inner :ball raceumember has a;flangerportron 1| 5 x-whichiformshthe race rfcr' fthe' eballs i Hi.

This ass embly .iis'Tleldibnto :the'; headiilJoy; means'GfibhGOHbl-if'bdll' race in :which isrsecuredid-the head 4 by means ofscrews such as II. A locating -;pin 1 2 is provided i toiiacilitate {theassembly improper relationship;-

From the foregoing it will beiseemzthatcthe vane assembly isrotatablewithin thex-hea'di as- The fuse disclosed =inathissapplicationaissdesi-gned Ifor" use' on theitaiL of a-bombi ,Thus;.--as

the--s=the :bomb is dropped theair stream pasty-the end of sleeve 2| isprovided with a gear wheel 22. Both of these gear wheels'are in meshwith an elongated pinion 23 mounted on the pinion pin 80 whose righthand end is driven into the head portion 4 and whose left hand end issupported in a hole in the plate l3 Whichis clamped vbetween the outerball race In and the head 4.

Gear wheel 22 has one more tooth than gear wheel I8 and as the vaneassembly is rotated 'by the air stream as the bomb is falling, therotation of gear Wheel l8 rotates pinion 23 which in" turn rotates thegear 22. In View of the difference in number of teeth, the gear 22 andthe sleeve upon which it is mounted gradually rotates relative to thehub I1 and as it rotates its left hand thread screws out of the hub l7moving the sleeve to'the right as viewed in Fig. l. The pinion 23 islong enough so that both gear wheels stay in mesh therewith until thesleeve 2| has been completely screwed out of hub II.

The sleeve 2| is provided with a center bore through which extends thefiring pin 28. This firing pin is provided with a striker 26 in threadedengagement therewith and the striker is locked on to the pin by means ofthe striker nut 21 and lock washer 19. r

The sleeve 2| as shown'in Figs. 1 and extends beyond the vane nut 20 andinto the central hole of a safety block 25.

This circular safety block has part of its wall cut away so that it canbecome disengaged from the head assembly when the sleeve 2| is moved tothe right by the The right hand end of hub I7 is provided with a gearwheel l8 and the right hand in the body by means of screws such as 53.This timing unit forms no part of the present invention and has,therefore, merely been indicated in the drawings.

It is suflicient for the purpose of this application to state that thehub 41 is rotated by the timing unit at a predetermined rate determinedby the time range desired for the particular fuze. Secured to the hub 41is a cam and disc assembly comprising the timing disc 5|, the hubportion 50, and the cam 49 which is mounted on the hub 48. The firingpin 28 extends through a central hole in the disc, hubs and plates ofthe timing unit.

As illustrated more clearly in Fig. 4, the firing pin is held in itscocked position by means of the engagement of the firing pin ring 33with the slabbed portion of the cocking pin 35. The

rotation of the vane assembly. However, as long as the sleeve is in theposition shown in the draw- 'ingthe safety block can not be removed andit 'serves as a safety device to prevent operation of the firing pin.

-' A striker stop 29 is normally wedged between the striker and thesafety block to keep the tension of the firing pin spring from thecocking pin. This striker stop is removed when the bomb is mounted onthe plane.

Fastened within'the cavity in head 4 is a firing pin spring sleeve 30which is retained in the pin ring 33 which is pinned to the firing pinby pin 34. In its set position, as shown in Fig. 1, the firing pin ring33 is in engagement with the slabbed surface of a. cooking pin 35rotatably mounted within the head 4. This cocking pin 35 is providedwith a cooking pin screw 36 which extends beyond the head 4 into thespace within body 'A channel is provided in head 4 for the passage ofthe cocking pin screw 36 when the cocking pin is rotated.

Mounted within the body is a timing unit indicated generally by thereference character 45.

' This timing unit is made up of a number of plates such as 46 which areheld together by means of suitable screws. The timing unit is retainedcocking pin screw 36 is retained by the hook 39 of the firing lever 31which is mounted on the head 4 by means of screw 38.

The tail 40 of this firing lever is in engagement with a laterallyextending projection 43 of the timing disc lever 4| which is alsomounted on the head 4 by means of screw 42. The bent up portion 44 oflever 4| serves as a cam rider and is in engagement with the peripheryof the timing disc 5|. Thus the spring pressure of the firing pin spring32 tends to rotate the cocking pin 35 in a clockwise direction as viewedfrom the left in Fig. 4 and the pressure of the cooking pin screw 36against the inner camming surface of hook 39 tends to rotate lever 31 inthe direction indicated by the arrow. This force is in turn transmittedto lever 4| tending to rotate this lever in a counterclockwise directionas indicated by the arrow, thereby maintaining the cam rider 44 againstthe edge of the timin disc 5|. The timing movement 45 is in woundcondition and tends to turn the hub and cams mounted thereon in acounterclockwise direction as seen in Fig. 3. The movement is preventedfrom operating by means of an arming pin 68 which has a reduced endportion 69 normally in engagement with the notch 52 in the timing disc5|. This arming pin 68 has an enlarged head portion 1| which is retainedin position by an arming wire (not shown) passing through the hole 12and holes in the arming pin bracket 13. The arming pin is urged to theright by means of the arming pin spring 10.

The body is provided With a transverse bore in which is contained thedetonator slider 54. Slider 54 carries the detonator 55 and is normallyheld in the position shown in Figs. 1 and 2 of the drawing with thedetonator out of the path of operation of the firing pin. The slider isheld in this position by engagement of the shoulder 82 (Fig.2) with aslabbed portion of the arming stem 60 which is rotatably mounted in thebody This arming stem 60 is bent over at its left hand end as seen inFig. 1 to form a cam rider portion 62 which normally rests on the cam 49as seen in full lines in Fig. 3 of the drawing.

The arming stem 60 is provided with a groove engaged by a screw 6| inorder to retain it in proper position. The detonator slider 54 is urgedto its armed position by means of the slider spring 51 which iscontained in the hollowed out end of the slider 54 and bears against theslider retaining plate 58 which is held to the body by means of screws59. The other endof the slider is reduced in cross section and isadapted to slide in and is guided by the bore 56 when the slider ismoved to armed position. A-groove 83 is provided in' the slider body andthis groove amort ze "fid is contained-a slider-lock 'pin 65 which isadapted to enter thedepression 63 and lock the slider in armed positionwhen it is movedto such armed position by means of spring 51. The pin 65is urged to the left as'seen in Fig. 2 by means of the locking pinspring 66 which is maintained in position bythe closure screw- 61.

The right hand-end of 'thefuze body isprovided with external threads 1by means of which the fuze is screwed into the body of a bomb. The fuZeis also provided with a booster cup 8 threaded into the fuze body at 9and this bOStel'g1 cup is filled with a booster charge indicated at 75.A hole is provided through the right end wall of the fuze body I tocommunicate between the detonator 55 and the booster charge and thishole is provided with a closure cup 14 to prevent the booster chargefrom entering the fuze body.

Referring particularly to Fig. 3 of the drawing, it will be seen thatthe time of detonation of the fuze after the arming pin 68 is removeddepends upon the relative position of the cam rider 44 with respect tothe notch 52 in the timing disc. This relative position may be adjustedby rotating the head assembly within the fuze body I. A scale isprovided on the fuze head which scale cooperates with a zero index onthe fuze body to indicate the time setting of the fuze. When the bomb towhich this fuze is attached is loaded in the plane, the striker stop 29is manually removed. Th arming wire which retains the arming pin 68 inposition and which also passes through a hole in vane I9 is thenattached to the bomb rack.

When the fuze is dropped this arming wire is pulled out, therebyreleasing the arming pin 68 which is forced out of the notch in timingdisc 5| by means of spring ill. The timing movement 45 therefore beginsto operate, turning the timing disc El and cam 49 in a counterclockwisedirection as seen in Fig. 3. Approximately three seconds later the camrider portion 62 of the arming stem 60 drops off the cam 49 and assumesthe position shown by the dotted lines in Fig. 3. Rotation of the armingstem Eli releases the shoulder 82 of the detonator slider and thisslider is moved to armed position by spring 51 carrying the detonator 55directly into line with the firing pin 28. As soon as the bomb begins tofall through the air, the air stream rotates vane l9 and by means of thedifferential action between gear wheel !8, pinion 23, and gear wheel 22,the sleeve 2| is screwed out of the hub l1 moving to the right towithdraw the left hand end thereof out of the safety block 25. As soonas the sleeve is removed from the safety block, the latter drops off ofthe fuze, being thrown out by centrifugal force, thereby clearing thestriker head so that the firing pin can operate to detonate the fuzeafter the elapse of the set time interval.

The timing disc 5! continues to be rotated by the timing movement untilthe notch 52 is engaged by the cam rider 44. The rider 44 drops into thenotch causing lever 4! to rotate and the projection 43 to disengage thetail 40 of lever 31. The cooking pin screw 36 therefore cams the hook 39out of the way and permits the cocking pin 35 to rotate, disengaging itsslabbed latching edge from the firing pin ring 33. As soon as the firingpin is released the spring 32 forces 6 "the'firin'g "pin -28'toitherightias. seen inili'igz-iil,

causing the *poiriter' end fof-rthe .pinr'to :enterflthe detonatorfifigexplo'ding the-charge whichzis'ztransmitted I to the booster:charge' 115. This -t in :turn

Referring lt'o Figi" 3, the fuze vcan be adjusted to -a minimum ritimeinterval of approximately 5 seconds. Thus ith'eirider '44 which is.inengagement withlthe timing disc 5 l :caniberotated: to :a

position seen.above ithe-notch 52, but teventrwith this setting it willbe'apparent that ithe :arming stem.cam.rider. 62 will disengage cam 49in order to .arm theifuze.beforezrider 44 enters notch 52 to detonatethe fuze. Thus, the delay interval for moving "thede'tonator-from*safety to armed position-(is Jfixed whereas -the time -intervalbetween the release of the bomb and detonation of the bomb may beadjusted to suit the particular requirements. However, the detonator isalways moved to armed position before the firing pin can be released bythe timing disc 5|.

The particular embodiment of the invention disclosed and described inthis application is a fuze adapted to be used on the tail of a bomb.However, as pointed out above, the fuze is equally adaptable for use asa nose fuze, it merely being necessary in this case to reverse the ballrace to provide the proper bearing surface for rotation of the vaneassembly. A shorter vane may be used when the fuze is used as a nosefuze.

Although only a particular embodiment of the invention has beendisclosed herein, it will be apparent to those skilled in the art thatvarious modifications and changes may be made Without departing from thespirit of the invention as defined in the following claims.

What is claimed is:

1. In a bomb fuze, a spring biased firing pin, a latch for holding saidpin in cocked position, a mechanical time movement and a cam driventhereby, means controlled by said cam for releasing said latch,detonator carrying means and means for moving same to armed position,and a second cam driven by said time movement for releasing saiddetonator carrying means.

2. In a bomb fuze, a spring biased firing pin, a latch for holding saidpin in cocked position, detonator carrying means and means for movingsame to armed position, a mechanical time movement, a cam controlled bysaid time movement for releasing said detonator carrying means after afixed interval, and a second cam controlled by said time movement forreleasing said latch after a predetermined adjustable interval.

3. In a bomb fuze, a spring biased firing pin, a latch for holding saidpin in cocked position, a detonator carrying means and means for movingsame to armed position, a timing device and a shaft rotated thereby,means normally holding said shaft in a zero position, means forreleasing said shaft to start said timing device, a cam on said shaftfor controlling said latch to release said firing pin after apredetermined adjustable interval, and a second cam on said shaft forreleasing said detonator carrying means after a definite fixed interval.

4. In a bomb fuze; a spring biased firing pin axially mounted in saidfuze; a detonator carrying means normally held in safety position withthe detonator out of alignment With said firing pin; a timing device; ashaft surrounding said firing pin and rotatable by said timing device; acam cooperating with a follower for releasing said detonator carryingmeans, said cam being secured to said shaft; a second camcooperatlog-with a cam follower for-releasing said firing pin alsosecured to said shaft, said cams and cam followers being so positionedthat the former cam and follower must release the detonator carryingmeans to firing position before the latter cam and follower can releasesaid firing pin; means to prevent the movement of said cams from zeroposition before the bomb has left the bomb rack; and means to adjust theinterval between the start of said cam movement from zero position andthe release of said firing pin.

JOHN B. MACLEAN.

MAX E. SCHLENKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number Number 8 UNITED STATES PATENTS Name Date Zornig Aug. 10, 1937Zornig Sept. 28, 1937 Bold Feb. 13, 1940 FOREIGN PATENTS Country DateGreat Britain Feb. 16, 1928 Great Britain Aug. 3, 1933

